Are you over 40 and struggling to read small print? You might have presbyopia, a common condition affecting those who are approaching their 40s. It's one of the harsher realities of aging, but it's good to know that having presbyopia when you already wear glasses for distance vision doesn't mean you now need two pairs of glasses. Multifocal lenses, which rectify both near and distant objects, let you see clearly at all times, with one pair of glasses.
Multifocals are a vast improvement on bifocals. Bifocals corrected poor near and far vision, but often things in between were blurry. In an effort to create a better product, progressive lenses were developed, which provide wearers with a transition part of the lens which lets you focus on the area between near and far distances. Progressive lenses, which are also known as no-line lenses, are a type of multifocal lens featuring a subtly curved lens, instead of a sharp line dividing both parts of the lens.
There are several different brands of progressive lenses in the market. What is the difference? Older generation lenses depended on fixed designs that provided relatively small area for close viewing, as the transitional areas appear distorted due to the changing lens curves needed to change the lens power. HOWEVER, newer technology uses digital equipment that can customize the lens curves to great detail (like a camera that is 3 megapixels compared to 20 megapixels). More measurements are needed on frame size and shape, frame tilt, distance from a person's eye to widen the clear zones and reduce peripheral distortion. This is called free form technology, which is different from classical progressives or even digital fixed design progressives.
Bifocals are still used though; they are helpful for kids and teens who suffer from eye strain, which is the result of a difficulty focusing while reading. Adults who have problems adapting to progressives will also still obtain bifocals.
Even though it may appear to be an easy solution, avoid buying drug store bifocals. A lot of these types of glasses are one-size-fits-all, which means that the both lenses contain the same prescription and that the optical center of the lens is not customized for the wearer.
A badly fitted pair of glasses can lead to eye strain, discomfort and nausea. At a certain age, most of us cannot avoid presbyopia. But it's good to know that the right lenses can make it a lot easier.